D-loop mutations in mitochondrial DNA are a risk factor for chemotherapy resistance in esophageal cancer

Area of Science:

• Oncology
• Genetics
• Biochemistry

Background:

• Esophageal cancer is aggressive, with chemotherapy resistance a major treatment challenge.
• Mitochondrial DNA (mtDNA) mutates more readily than nuclear DNA and impacts cellular function.
• Chemotherapy-induced mtDNA mutations in esophageal cancer are not well understood.

Purpose of the Study:

• Identify chemotherapy-induced mtDNA mutations in esophageal cancer.
• Correlate these mutations with clinicopathological factors and chemotherapy resistance.
• Investigate the role of mtDNA mutations in treatment outcomes.

Main Methods:

• Next-generation sequencing was used to analyze mtDNA in esophageal squamous cell carcinoma (ESCC) cell lines and patient samples.
• Samples included pre- and post-chemotherapy cell lines and patient tissues.
• Analysis focused on identifying mtDNA mutations and their association with clinical data.

Main Results:

• Chemotherapy treatment led to an increase in mtDNA mutations, especially in the D-loop region.
• Mutations within the hypervariable segment 1 (HVS1) of the D-loop were associated with reduced mtDNA copy number.
• HVS1 mutations correlated with poorer chemotherapy response and decreased five-year survival rates.

Conclusions:

• Acquired HVS1 mutations in mtDNA following chemotherapy may drive treatment resistance in esophageal cancer.
• These findings highlight a potential mechanism for chemotherapy resistance and poor prognosis.
• Understanding these mtDNA alterations could inform strategies to overcome treatment challenges in esophageal cancer.